I've never really liked the rip of LTTP boulders which is present in Pure and Descendant, but awhile ago I discovered why: the original uses one black and three browns, whereas at some point someone recolored them for ZC by using two browns and replacing the darkest one with black.

So, I recolored the boulder from the LTTP set. But that led me to remake a few more tiles. First I added cracks to the new Pure boulders. Then I ripped the lava-spewing boulders from the LTTP set, which didn't look at all good in Pure's set of light browns, so I kept the lava portion, edited the regular boulder heavily, and combined the two. The lava can be changed to a variety of colors in each CSet.

Lastly, the half-submerged boulder is a combination of the LTTP boulder and the boulder in the water which was included in the Descendant tileset.

Enjoy.

Dart Zaiyder and Orion for LTTP set;
plith for Descendant;
Mr. Z et al for Pure Update ver 2.1.